Die-stock.



PATENTE-D JUNE 26, 1906. T. R. LEIGHTON.

DIE STOCK APPLICATION FILED JULY 31,1905.

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PATENTED JUNE 26, 1906.

T. R. LEIGHTON.

DIE STOCK.

APPLICATION FILED JULY31,1905.

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T. R. LEIGHTON.

DIE STOCK. APPLICATION FILED JULY 31,1905.

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UNITED STATES PATENT OFFICE.

DIE-STOCK.

Specification of Letters Patent.

Patented June 26, 1906.

Application filed July 31,1905- Serial No. 271,918.

To aZZ whom it may concern.-

Be it known that I, THOMAS R. LEIGHTON, a citizen of the United States, residing at East Cleveland, in the county of Ouyahoga and State of Ohio, have invented a certain new and useful Improvement in Die-Stocks, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

The object of the present invention is to provide an improved mechanism for threading pipes and to avoid the defects inherent in the structures hitherto known in the art. As is well known, it is necessary in cutting threads that the die -stock be guided so that the dies shall be concentric with the pipe, and this guiding has usually been obtained by means of sleeves sliding over the pipe itself. Such a method of centering the dies is objectionable by reason of the fact that the guiding sleeve or annulus frequently binds on the pipe and is defective in its action unless the pipe-surface is practically perfect in its contour. These prior guiding and centering devices are, owing to the fact that they operate in connection with the pipe, generally of necessity changed with each change in the size of pipe worked. In the structure which I have invented the centering and guiding of the dies is independent of the inequalities on the pipe-surface and is absolutely accurate without regard to the character or quality of the pipe and, further, avoids the necessity of changing the parts whenever the size of pipe is changed. Heretofore, also, the vise-jaws and dies have been adjusted by more or less complicated and expensive mechanism, necessitating a most exact construction and which are not capable of the most ready operation. The adjusting mechanisms which I employ are simple in their form, cheaply made, and by virtue of the mechanical movements employed capable of practically instantaneous operation. Heretofore it has been necessary after the pipe has been threaded to run the die-stock off the pipe and cut the pipe by a separate operation. In my device the cutting of the pipe can be accomplished while it is still held in the vise and without removing the diestock. These and many other advantages will appear from a more detailed description Referring to the accompanying drawings, Figure 1 is a front view of the vise-clamp. Fig. 2 is a front view of the die-stock, showing l the dies retracted and the cutter-blades advanced somewhat as they would appear after the threading operation had cease and the cutting operation had commenced. Fig. 3 is a perspective view of the adjustable die which I employ. Fig. 4 is a plan of a modified form of d1e. Fig. 5 is a plan, partly in section, of the device, showing the means by which the die-stock is centered on the pipe.

The vise by which the pipe is rigidly held during the threading and cutting operations comprises a frame A, having an extending bracket A, by which it may be secured to any suitable support. Slidably mounted on the frame are the vise-jaws A A which in the preferred form are each provided with an internally-threaded tubular socket A Within these sockets and mounted in the frame are right and left handed screw-threaded shafts A A, having secured at their outer ends gears A? A which mesh with two other gears A A, mounted on a straight shaft A also journaled in the frame. By rotation of the straight shaft it will be seen that the right and left handed screws will feed their respective vise-jaws in or out according to the direction of rotation of the straight shaft. This construction insures a synchronous movement of the jaws, so that when once the latter are centered no further attention need be given to the adjustment, as their respective reciprocations are not independent, as in the ordinary structure, but will always be relatively the same.

Projecting from the upper and lower sides of the vise-frame are plates A A to which I rigidly secure a projecting guiding-hub A", which is adapted to receive a hollow sleeve projecting from the rear of the die-stock. The die-stock is preferably formed with regard to its main structure of an integral casting B, but is provided with such retainingplates as may be necessary in its detail structure. It is provided with sockets B B for the operating-handles and slideways B B B B for the dies and the cutters, respectively.- The dies B B are snugly and closely held a ainst lateral or sidewise movement by the si e walls of the ways B and are provided with projecting which they are advanced or retracted and rigidly held against endwise movement at any desired point. These tail-screws B are separate from the dies and have dovetail connection therewith in such manner that they may be separated and the tail-screw secured tail-screws B by to either end of the die, thus admitting of reversal, so that each die inaycarry two threads of different gage. like the screw shafts of the vise, right and left handed, but pass through internallythreaded gears B B, whch are borne in the die-stock. These nut-gears B mesh with gears B B on a straight shaft B also mounted in the die-stock, and upon the rotation of the straight shaft the tail-screws B Will each be fed in or out according to the direction of rotation, carrying with them the dies B. The dies herein shown are made the subject of my divisional application, No. 282,905, filed October 16, 1905, wherein their essential features are claimed. -The dies are each made of sections, as will be seen by, reference to Figs. 3 and 4, a structure which admits of them being separated when it is desired to grind the threads and which, as will be ob vious to any one skilled in the art, affords an unrestricted play of the grinding-wheel upon the threadsan advantage which is of the greatest importance. In the form shown in Fig. 3 I have shown the two sections as held together by a dovetailed tongue B and groove. The function of this tongue, broadly, is to hold the parts against relative endwise movement, While the undercut or dovetail structure also serves to retain the two sections against sidewise separation, which is of course an advantage in keeping the parts from becoming mismated While outside the die-stock. It may be said, however, that While the parts are in the frame no sidewise separation would be possible, even though the two sections were held together by no other means than the frame itself.

In the form shown in Fig. 4 I have provided a right-angle tongue B and groove, with a binding-screw B locking the tongue in the groove. For certain purposes this construction may be deemed preferable; but the essential feature of each of these struc tures is that there shall be an interlocking tongue and groove, which will maintain the two parts against relative endwise slip.

Projecting from the rear of the die-stock is the hollow sleeve 0, fitting within the hub A", rigidly secured to the vise-frame. The sleeve 0 and hub A are accurately centered in construction and are snugly fitted to each other in such manner that while the sleeve is firmly positioned and guided by the hub it may be slid in and out by the operator. The inner diameter of the sleeve is slightlylarger than that of the largest pipe which it is designed to thread, so that there is no contact between the hub and the pipe, and therefore no resulting binding action.

Between the guiding-sleeve and the ways for the dies I construct the slideways B B for the cutters D D, which are of any suitable number-preferably twoand are reciprocated in and out by means of screw-stems D The two tail-screws are D, fitted. within internally-tl'ireaded star- Wheels D D*, which latter are each retained against reciprocatory movement by a lug D projecting from the frame into an annular groove on the wheel. The threads on the cutter-stems are of like character in each instance, and their reciprocation is effected by the rotation of the star-wheels. For the purpose of securing automatic rotation of these wheels I have provided pins E E, projecting from the rigid hub A, of a proper length to be in the path of the star-wheels when the guide-sleeve O has been pushed into the hub to the limit of its movement.

In the operation of my device the cutters and the dies are properly retracted and the pipe-stock placed between the vise-jaws. Upon turning the straight shaft in the viseframe the jaws are brought together and rigidly secure the pipe centrally within the hub. The die-stock is then drawn out from the vise a distance suflicient to permit of the proper width of thread being out before the starwheels come in contact with the pins projecting from the hub. Byrotation of the straight shaft in the die-stock the dies are then brought down against the pipe-surface and made to bite against the same. By reason of the fact that the pipe is rigidly held by the vise-jaws and the vise-jaws are centered with regard to the hub, which latter guides and centers the die-stockthrough the hollow sleeve projecting from the die-stock, it will be seen that an absolutely perfect centering of the dies with regard to the pipe has been secured and the advance of the dies upon the pipe will be rigidly accurate and without variation. When the threading has proceeded to the proper point, the dies are released from the pipe by the simple rotation of the straight shaft and the die-stock is then slid forward until the shoulder at the base of the hollow sleeve abuts against the end of the hub. At this point the projections from the hub stand in the path of the star-wheels, and the con tinued rotation of the die-stock will automatically and gradually feed the cutters into the pipe-stock and effect a speedy and easy cut ting of the latter. Should it not be desired to cut the pipe at the precise point which would be indicated by this operation, it is obvious that the vise jaws may be readily loosened and the pipe-stock fed along until the desired point is reached, where, upon reclamping of the vise, the cutting may be eflected.

It is obvious that certain equivalents of the mechanical movements herein described may be used, and I wish it to be understood that I regard such equivalents as coming within the spirit of my invention, which is broad and comprehensive in its character.

Having described my invention, I claim- 1. A stock carrying a plurality of cutters disposed so that their individual tendency to bend the pipe will be counteracted and means for simultaneously feeding said cutters into the pipe, said feeding means being adapted to be rendered effective upon relative rotation between the stock and the pipe by contact with a part rotatively independent of said stock.

2. A vise-frame, a stock carrying a plurality of cutters so disposed that they mutually counteract each others thrust, and means on the stock adapted to feed the cutters simultaneously, said means rendered effective upon the relative rotation of the stock and Vise.

3. A vise-frame, a stock carrying a plurality of cutters disposed to mutually oppose the individual thrusts, and means on the stock adapted to feed and retract said outters, said feeding and retracting means being effective upon relative rotation between the vise and stock.

4. A vise-frame, a stock carrying a plurality of cutters disposed to center the pipe by their thrusts, centering means adapted to maintain the stock in a definite position relative to the vise-frame, and means for effecting simultaneous and equal movement of the cutters, said moving means being rendered effective by relative rotation between the stock and vise.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

THOMAS R. LEIGHTON.

Witnesses J. W. WOODWARD. E. M. LEwIs. 

